Shoe system with a resilient shoe insert

ABSTRACT

The shoe system comprises a shoe that has an upper rim section. A shoe sole is disposed inside the shoe and has a top layer. A shoe insert has a stiff first member and a resilient second member attached to the first member so that the first member is attached to the top layer of the shoe sole. The second member is movable between a compressed position immediately adjacent to the first member and an expanded position remote from the first member. The first member is disposed a first distance from the upper rim section when the second member is in the compressed position and the first member being disposed the same first distance from the upper rim section when the second member is in the expanded position.

PRIOR APPLICATION

[0001] This is a continuation-in-part application of U.S. patentapplication Ser. No. 09/326,729; filed Jun. 7, 1999.

TECHNICAL FIELD

[0002] The present invention relates to a resilient shoe spring systemthat is integrated with a shoe system.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] Users and developers of elastic shoes and shoe soles areconfronted with the problem of back injury and releasing the storedenergy in the shoe sole in a manner which improves walking and runningeconomy while at the same time achieving adequate bio-mechanical shoestability and cushioning. Many shoe manufacturers have concentratedtheir effort on chock absorption by permanently increasing the thicknessof the shoe sole. This has resulted in a slight change of the anglebetween the ankle and the foot that may weaken the tendons of the foot.This change of the angle may also lead to instability and reducedbio-mechanical effect.

[0004] Many efforts have been made to develop an effective springmechanism for shoes or shoe soles. However, the earlier proposed springdesigns for shoe soles have not been entirely satisfactory. Despite manyelaborate shoe sole solutions, back injuries and other injuries arestill common due to poorly designed shoes. Injuries due to poor shoedesigns are particularly common in sports and heavy duty workactivities.

[0005] One important function of a shoe, such as a running shoe, is toprotect the foot from the stresses of running. The forces and motionsthat occur in different sports vary greatly. Because of thesedifferences it is important that active participation in varied sportsrequire varied shoes. For example, tennis and other racquet sportsrequire much side-to-side motion and the shoe must provide lateralstability. If the shoe is unstable and has high heel elevation when theathlete is moving from one side to another the likelihood is great theathlete may suffer an ankle sprain. The majority of conventional shoesare not well designed. Some of insufficiencies of the current shoedesigns may be overcome by the present invention.

[0006] The shoe system of the present invention comprises a shoe thathas an upper rim section. A shoe sole is disposed inside the shoe andhas a top layer. A shoe insert has a stiff first member and a resilientsecond member attached to the first member so that the first member isattached to the top layer of the shoe sole. The second member is movablebetween a compressed position immediately adjacent to the first memberand an expanded position remote from the first member. The first memberis disposed a first distance from the upper rim section when the secondmember is in the compressed position and the first member being disposedthe same first distance from the upper rim section when the secondmember is in the expanded position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a side view of a shoe insert of the present invention;

[0008]FIG. 2 is a side view of a shoe adapted to receive the shoe insertof FIG. 1;

[0009]FIG. 3 is a rear view of the shoe in a vertical position alongline 3-3 of FIG. 2 with the shoe insert of FIG. 1 placed inside theshoe;

[0010]FIG. 4 is a rear view of the shoe along line 3-3 of FIG. 2 whenthe ankle is disposed in an inwardly sloping position;

[0011]FIG. 5 is a side view of a person standing straight up on the shoeof the present invention;

[0012]FIG. 6 is a side view of a person standing on the shoe and leaningforward;

[0013]FIG. 7 is a side view of an alternative embodiment of the shoeinsert of the present invention;

[0014]FIG. 8 is a top view of the shoe insert;

[0015]FIG. 9 is a top view of a second embodiment of a shoe insert forthe right shoe;

[0016]FIG. 10 is a top view of the second embodiment of the shoe insertfor the left shoe;

[0017]FIG. 11 is a bottom view of a third embodiment of a shoe insert;

[0018]FIG. 12 is a side view of a fourth embodiment of a shoe insert;

[0019]FIG. 13 is a side view of a fifth embodiment of a shoe insertintegrated with a shoe sole;

[0020]FIG. 14 is a side view of the fifth embodiment of the shoe insertin a compressed position; and

[0021] FIGS. 15A-D are schematic flow diagrams of a pressing techniquefor manufacturing the shoe insert.

DETAILED DESCRIPTION

[0022] With reference to FIGS. 1-8, the present invention is a shoesystem 10 having a resilient shoe insert 11 including a stiff firstsupport member 12 that may be made of a carbon fiber reinforcedcomposite material or any other suitable material that is relativelystiff. The first member 12 has a flexible and bendable fore end 14 and astiff aft end 16. The fore end 14 has a cavity portion 18 thatterminates in a slightly upwardly curved end section 20. It is to beunderstood that the fore end is preferably made of a flexible andbendable material that may be cut to size by a pair of scissors totailor the shape of the fore end 14 to the shape of the shoe system andthe foot. Another reason for using the flexible material at the fore end14 is so that the toes of the foot may fully cooperate with the fore end14 when walking and moving about.

[0023] The stiff aft end 16 has a cavity portion 22 that terminates in aslightly upwardly curved end section 24. A stiff middle section 26 ofthe member 12 is convex shaped relative to the concave cavity portions18, 22. A holder mechanism 26 is attached to an underside 28 of thefirst member 12. The holder mechanism 26 includes a short end wall 30that is perpendicular to the member 12 and a long support wall 32 thatis perpendicularly attached to the end wall 30 to that the underside 28,the end wall 30 and the support wall 32 define a receiving pocket 34that is facing the aft end 16. Preferably, the end wall 30 is attachedto the underside 28 on the first member 12 at a point 29 that is at afront end portion of the middle section 26. In the preferred embodiment,the first member 12 is stiff all the way from the place of attachment atthe point 29 of the end wall 30 to the end section 24 and bendable fromthe point 29 to the end section 20.

[0024] A second member 36 has a fore end 38 that is insertable into thereceiving pocket 34. More particularly, the second member has the foreend 38 and an opposite aft end 40. The fore end 38 has a slightlydownwardly curved end section 42 and the aft end 40 has an upwardlycurved end section 44 so that the second member 36 is somewhat S-curved.When the second member 36 is inserted into the receiving pocket 34, theend section 44 is aligned with the end section 24 of the first member 12so that a gap 46 is formed between the first member 12 and the secondmember 36.

[0025] An important feature of the present invention is that the secondmember 36 is springy and resilient while the first member 12 isgenerally stiff except for a bendable toe portion. As is explainedbelow, a heavier person may select a stiffer second member than alighter person to prevent the second member 36 from abutting or restingagainst the first member 12 when the heavier person is standing on thefirst member 12 with the second member 36 inserted into the receivingpocket 34. Preferably, the second member 36 should be sufficiently stiffso that the second member 36 does not bottom out even though the personis actively using the shoe insert 11 disposed in the shoe. For example,when a person is standing straight up (as is shown in FIG. 5) so thatthe shoe insert 11 is subjected to the greatest weight, the first member12 form a minimum angle alpha relative to the second member 36 but theangle should not be zero. The angle alpha increases when the personbends his/her knees or leans forward, as is shown in FIG. 6, so that anincreasing amount of the body is supported by the front portion of thefoot and less weight is exerted upon the second member 36. It is alsopreferred that the stiffness and the shape of the second member 36 aresuch that the first member 12 does not bottom out even though the personis jumping or actively using a shoe 48.

[0026] Other factors that determine what stiffness to use for the secondmember 36 include the type of activity the shoe is going to be used forand whether the walking/running surface is hard, soft and uneven. Theshape of the second member 36 may also be varied depending on the needsof the user. For example, a second member having a more bent fore endcreates a bigger gap 46 between the second member and the first memberwhen the second member is inserted into the holder 32. A bigger gap 46may reduce the risk of bottoming out and also changes the angle betweenthe foot and the ankle.

[0027] Because the first member 12 is stiff, the shape of the firstmember is maintained and the foot is provided a full support althoughthe second member 36 may move relative to the first member 12. In otherwords, the first member 12 provides good support to the foot althoughthe second member 36 may be compressed against the first member 12 andlater permitted to move back to the relaxed expanded position dependingupon how the shoe is used in, for example, a sport activity.

[0028] As best shown in FIG. 2, the shoe 48 may have a preformed shoesole 50 that has an upper surface 52 that is shaped to snugly receivethe shoe insert 11. The shoe 48 has a heel section 51 and a toe portion53. The shoe sole 50 is preferably made of a flexible material such asrubber or plastic. The upper surface 52 has an upwardly curved frontportion 54, a convex middle portion 56 and a slightly upwardly curvedaft portion 58 to support the sections 20, 26 and 24, respectively, ofthe first member 12.

[0029] An important feature is that the shoe sole defines an angularcurved groove 60 that is dimensioned to receive the second member 36.The groove 60 extends backwardly and angularly downwardly towards a heel62 of the shoe 48. A triangular wedge 64 is disposed between the uppersurface 52 and the groove 60. The wedge 64 is removably attached to thesole 50 so that the wedge 64 easily be removed to make it convenient toinsert and remove, particularly, the second member 36 of the shoe insert11. The wedge 64 is made of a very flexible material so when the secondmember 36 is urged towards the first member 12 by the weight of theuser, the wedge 64 is deformed and compressed accordingly.

[0030] The shoe 48 may also be used with the shoe insert 11 placed onthe upper surface 52 but with the wedge 64 removed. An one-way valve 66is attached to a back end 68 of the shoe 48. A channel 70 may be definedin the shoe sole 50 so that the valve 66 is in fluid communication witha space 72 that is formed between the first member 12 and the secondmember 36. Of course, the wedge 64 may extend all the way back to thesection 58 of the shoe sole 50 so that there is no need for a channel.

[0031] When the second member 36 is pressed towards the first member 12so that the shoe insert 11 is in a compressed position, an over pressureis formed in the space 72 that may flow into the channel 70 and outthrough the valve 66 to provide good mechanical ventilation inside theshoe. Any under pressure that may be formed in the space 72 when thesecond member 36 is permitted to move from the compressed position backto its original expanded position away from the first member 12 may beequalized by sucking in air from an upper part 74 of the shoe 48 such asthe opening 76 or the open areas adjacent to the shoe laces 78. Itshould be understood that the valve 66 may also be a two-way valve sothat the valve may be used to compensate for both over-pressure andunder-pressure in the space 72. In this way, the valve 66 may functionto circulate and possibly bring in or suck cool air into the inside ofthe shoe when the second member 36 is permitted to expand from thecompressed position. A filter 79 may also be placed in the valve 66 toprevent dust and other undesirable particle from entering into theinside of the shoe 48 when the shoe inlet 11 is expanding.

[0032] As best shown in FIG. 3, the first member 12 and the secondmember 36 are substantially parallel when a person is standing straightup without leaning sideways. The first member 12 may have vertical sidewalls 81, 83 to prevent the foot from sliding sideways and put unduepressure on the side wall of the shoe. However, when the person moves ina sideways direction so that an ankle 90 is in an inclined position, theweight distribution of the shoe may be uneven, as shown in FIG. 4, sothat the second member 36 is twisted slightly relative to the stifffirst member 12 to create a torsion force about an outside portion 82 ofthe second member 36. The second member 36 may have a first thickness d₁on an inside portion 80 and a second thickness d₂ on the outside portion82. The second thickness d₂ is greater than the first thickness d₁ sothat the second member 36 is only permitted to twist relative to thestiff first member 12 when the ankle 90 is leaned inwardly, as shown inFIG. 4, if the shoe 48 shown is a shoe for the right foot. In otherwords, the second thickness at the outside portion 82 is sufficientlythick to make the outside portion 82 of the second member 36 rigidenough to prevent any relative movement between the first member 12 andthe second member 36 at the outside portion 82. Because the insideportion 80 is twistable, there is less need to bend the ankle relativeto the foot, thus exposing the ankle to less strain, when the person isstanding with the legs wide apart. For example, it is common to standwith the legs wide apart when waiting to return a serve in tennis.Another situation that may put extra strain on the ankle is when runningalong a surface that is sloping sideways. The twisting of the insideportion 80 generally results in less risk of straining the foot becausethe angle change between the ankle and the foot as a result of leaningthe ankle inwardly is reduced.

[0033]FIG. 7 shows an alternative embodiment of the present invention.The shoe insert 100 includes an extended back support section 102 thatextends above the heel of the foot to partly protect the Achilles tendonand the heel of the foot. The support section 102 reduces any excessiverubbing between the heel of the foot and the rear inside wall of theshoe. Excessive rubbing may cause blisters as the shoe insert 11 iscompressed and expanded. Similar to the shoe insert 11, the shoe insert100 has a stiff first member 104, a resilient second member 106 and abendable and flexible fore end 108 that may terminate at a toe portion109 that extends over the toes of the foot to protect the toes while thetoe portion 109 may follow the movement of the shoe insert. A resilientrubber pad may be adhered to a bottom side of the fore end 108 toprovide extra comfort. The first member 104 and the second member 106form an angle alpha therebetween. This embodiment is particularly usefulfor working shoes and other types of heavy duty boots.

[0034] As best shown in FIG. 8, a transition area 77 between the firstmember 12 and the soft and flexible fore end 14 may be a curved sectionthat is formed according to the support area of the foot that isdisposed behind the toes.

[0035]FIG. 9 is a top view of a second embodiment of the shoe insert ofthe present invention. A shoe insert 200 has a transition area 202 (thatis equivalent to the transition area 77 of FIG. 8) that extends at anangle so that a distance (x) at an inside 204 of the shoe insert 200 islonger than a distance (y) at an outside 206. In other words, theflexible member is longer at the inside 204 than the outside 206 so thatthe inside 204 may flex (as shown in FIG. 4) while the outside 206 isrelatively stiff. Similarly, FIG. 10 shows a top view of a shoe insert210 for the left shoe that has a transition area 211 and an inside 212that has a length (x) that is longer than a length (y) of an inside 214.FIG. 11 is a bottom view of a third embodiment of the present invention.A shoe insert 216 has an angular transition area 218 in addition to aflexible member 220 that has a softer inside portion 222 and a stifferoutside portion 224. In the third embodiment, it is not necessary thatthe transition area extends at an angle because the inside portion 222is already softer than the outside portion 224. FIG. 12 is a side viewof a shoe insert 230 having a plurality of flexible members 232, 234,236 attached to an underside 238 of the shoe insert 230 so that both theresiliency and the resiliency on the inside and the outside may beadjusted to the specific needs of the user of the shoe insert 230.

[0036]FIGS. 13 and 14 show a fifth embodiment of the present invention.A shoe 300 has a shoe sole 302 including an upper layer 303 with a shoeinsert 304 integrated with or built into the sole 302. The shoe 300 hasa toe portion 330 and a heel portion 332 and shoe sole 302 has a bottomside 305. The insert 304 has a relatively stiff upper segment 306 and abendable lower segment 308 that is attached to a lower side 310 of thesegment 306 at a mid-section 312 of the upper segment 306. The segment306 is, preferably, attached to a back piece 301 that is disposed at theupper segment 303 adjacent to a back side 309 of the shoe 300. The uppersegment 306 and the lower segment 308 has a space 307 definedtherebetween. The space 307 may be filled with air or a verycompressible and expandable material. The space 307 may be completely orpartially filled with a material. For example, the material may includesegments of elastomers to change the spring characteristics of theinsert 304. Stiffer elastomer segments may be used if the person isheavy and less segments or less stiff segments may be used if the personis relatively light.

[0037] An important feature is that the segment 306 is stiff and isattached to the sole so that the segment 306 does not move relative tothe shoe although the lower segment 308 may move relative to the uppersegment 306. This means that a foot inserted into the shoe 300 remainsin the same position regardless of the flexural movements of the lowersegment 308. When the lower segment 308 is in an expanded unloadedposition (see FIG. 13) the distance between the upper segment 306 and abottom side 305 of the sole 302 is a distance (A). However, when theshoe 300 is put under a load (L) (see FIG. 14), the lower segment 308moves into a compressed position towards the upper segment 306 to reducethe distance between the upper segment 306 and the bottom side 310 to adistance (B) that is smaller than the distance (A). When the lowersegment 308 is in the compressed position, the segment 308 urges theupper segment 306 upwardly into the expanded position.

[0038] An important feature of the present invention is that uppersegment 306 is disposed at a distance (X) from an upper rim 314 bothwhen the lower segment 308 is in the expanded position, as shown in FIG.13, and in the compressed position, as shown in FIG. 14. This means thatthere is little risk of blisters on a foot 316 placed in the shoe 300between there is no relative movement between the foot 316 and the shoe300.

[0039] With reference to FIGS. 15A-D, the shoe insert of the presentinvention is preferably made by using a unique pressing method. Themethod relies on a tool 400 having a upper component 402 and a lowercomponent 404. The component 402 has a cavity 406 defined therein thathas the same shape as the upper segment 306 and the component 404 has acavity 408 defined therein that has the same shape as the lower segment308. As best shown in FIG. 15B, the components 404, 406 are separatedfrom one another. A pre-impregnated upper component 410 is placed, asshown by an arrow A1, inside the cavity 406. The component 410 has anelongate front end portion 409 and an elongate back end portion 411 anda shape that is similar to the shape of the cavity 406. A preimpregnatedlower component 412 is placed in the cavity 408 and has a shape that issimilar to the shape of the cavity 408. Preferably, the components 410,412 and 414 are made of polymer composites such as carbon and/or glassfiber reinforcements that are impregnated with a suitable resin. Thecomponents may be fully or partly impregnated. Preferably, the toeportion of the components 410, 412 are partially impregnated to obtainan increased bendability. The resin could be a suitable thermoplastic,such as a thermoplastic polyester, or a thermoset resin, such as epoxy.Of course, other suitable polymers can also be used.

[0040] The component 412 has an elongate front end portion 413 and anelongate back portion 415. A U-shaped third component 414 is placedbetween components 410, 412 to improve the physical properties of afinished insert 424. The component 414 has continuous fibers extendingalong the entire component 414 from one end of the U-shaped component toan opposite end of the component 414. Surprisingly, the component 414substantially reduces fiber breakage and other failure characteristicsof the insert 424. Preferably, a sandwich construction is used so thatthe stiffer carbon fibers may be placed on each side of the U-shapedcomponent 414 that is, preferably, made of the less stiff glass fibers.Glass fibers have better springing characteristics compared to carbonfibers due to the high fatigue resistance properties of glass fibers. Ingeneral, glass fibers are not as brittle as carbon fibers. Carbon fibersmay be used to partially or fully in the components 410, 412. However,carbon fibers may also be used on the inside of the component 414 in theform of carbon fiber tapes that extend from a back portion 411, 415,respectively, of the components 410, 412 towards a bottom 421 of thecomponent 414. More particularly, the component 414 has the bottom 421,an upper leg 416 and a lower leg 418. The upper leg 416 is placed alongan inside 420 of the back end portion 411 and the lower leg 418 isplaced along an inside 422 of the back portion 415. In this way, boththe upper leg 416 and the end portion 411 are placed inside an elongateback end 417 of the cavity 406 and the both the lower leg 418 and theback end portion 415 are placed inside an elongate back end 419 of thecavity 408. This means that the above described sandwich constructionmay be used on the legs 416, 418 of the components 410, 412 togetherwith the component 414. Preferably, the sandwich construction is notused for the portions 409, 413. A resilient filler piece 423 may beplaced between the legs 416, 418 prior to compression of the tool. Thehardness of the piece 423 may be adjusted depending upon the weight ofthe user. For example, a more rigid piece 423 may be used if the user isheavy and a softer piece 423 may be used if the user is relatively lightweight.

[0041] As best shown in the FIG. 15c, when the components 410, 412 withthe third component 414 placed therebetween, are properly positioned inthe tool components 402, 404, the components 402, 404 are moved towardsone another, as shown by arrows A2 and A3. A pressure of between 2-40bar is applied to the components 402, 404 for several minutes and thetemperature is raised to between 100-250° C. to enable the resin of thecomponents 410, 412 to enable a thermoplastic resin to melt or athermoset resin to cure. The tool 400 may then be rapidly cooled beforethe components are removed from the tool 400.

[0042] When the components 410, 412, 414 are cured into an integratedshoe insert 424, the tool components 402, 404 are separated from oneanother and the insert 424 is removed from the components 402, 404, asshown by an arrow A4 in FIG. 15D. The insert 424 is now ready to beintegrated with or built into a shoe sole as the insert 304 is shown inFIGS. 13-14.

[0043] While the present invention has been described in accordance withpreferred compositions and embodiments, it is to be understood thatcertain substitutions and alterations may be made thereto withoutdeparting from the spirit and scope of the following claims.

We claim:
 1. A shoe system, comprising: a shoe having an upper rimsection; a shoe sole disposed inside the shoe, the shoe sole having atop layer; a shoe insert having a stiff first member and a resilientsecond member attached to the first member, the first member beingattached to the top layer of the shoe sole, the second member beingmovable between a compressed position immediately adjacent to the firstmember and an expanded position remote from the first member, the firstmember being disposed a first distance from the upper rim section whenthe second member is in the compressed position and the first memberbeing disposed the same first distance from the upper rim section whenthe second member is in the expanded position.
 2. The shoe systemaccording to claim 1 , wherein the second member is attached to anunderside of the first member.
 3. The shoe system according to claim 1 ,wherein a heel portion and a toe portion of the shoe are disposed at afirst height when the second member is in the compressed position andthe heel portion is disposed at a second height and the toe portion isdisposed at the first height when the second member is in the expandedposition, the second height is greater than the first height.
 4. Theshoe system according to claim 1 , wherein the second member is attachedto the first member and directed towards the heel portion of the shoe.5. The shoe system according to claim 1 wherein a U-shaped component isdisposed in a gap defined between the first member and the secondmember.
 6. The shoe system according to claim 5 wherein the U-shapedcomponent has a bottom that is immediately adjacent to a connectionpoint between the first member and the second member.
 7. The shoe systemaccording to claim 5 wherein the U-shaped component has an upper legthat is disposed along a back end of the first member and a lower legthat is disposed along a back end of the second member.
 8. A method ofmaking a shoe system having a resilient shoe insert, comprising:providing a shoe having an upper rim section and a shoe sole disposedinside the shoe, a shoe insert having a stiff first member and aresilient second member attached to the first member, a firstcompressible material being disposed between the first and secondmembers, the compressible material having a first hardness, the firstmember being disposed a distance (X) from the upper rim and a distance(A) from a bottom side of the shoe sole; putting a load (L) on the shoe;compressing the second member towards the first member while maintainingthe first member at the distance (X) from the upper rim and reducing thedistance (A) to a distance (B), the distance (A) being greater than thedistance (B), removing the first compressible material; and inserting asecond compressible material having a second hardness, the secondmaterial being harder and stiffer than the first material.
 9. The methodaccording to claim 5 wherein the method further comprises removing theload (L) and expanding the shoe sole so that the second member is movedrelative to the first member from the distance (B) back to the distance(A).
 10. The method according to claim 6 wherein the method comprisesraising a heel portion of the shoe when the load (L) is removed from theshoe.
 11. The method according to claim 5 wherein the method compriseslowering a heel portion of the shoe to a height that is the same as aheight of a toe portion of the shoe.